CN105453196B

CN105453196B - R T B system's sintered magnets and motor

Info

Publication number: CN105453196B
Application number: CN201480044345.5A
Authority: CN
Inventors: 金田功; 三轮将史; 中嶋春菜; 加藤英治
Original assignee: TDK Corp
Current assignee: TDK Corp
Priority date: 2013-08-09
Filing date: 2014-08-08
Publication date: 2017-12-22
Anticipated expiration: 2034-08-08
Also published as: US20160163434A1; DE112014003674T5; JP6274215B2; WO2015020181A1; US10410777B2; JPWO2015020181A1; CN105453196A

Abstract

The present invention provides a kind of R T B systems sintered magnet for having excellent corrosion resistance, and having good magnetic characteristic concurrently.The R T B systems sintered magnet is characterised by that the R T B systems sintered magnet has R₂T₁₄B crystal grain, by the adjacent above-mentioned R of more than 2₂T₁₄There is R Cu M C concentrating part in the crystal boundary that B crystal grain is formed, compared to above-mentioned R₂T₁₄In B crystal grain, the R (R is at least one kind of in Sc, Y and lanthanide series) of above-mentioned R Cu M C concentrating part, Cu, M (M is at least one kind of in Ga, Si, Sn, Ge, Bi), C concentration are all higher.

Description

R-T-B systems sintered magnet and motor

Technical field

At least one kind of of indispensable element is used as the present invention relates to the rare earth element using more than a kind (R), by Fe or Fe and Co More than transition metal (T) and boron (B) as main component R-T-B systems sintered magnet and possess R-T-B systems burn Tie the motor of magnet.

Background technology

Although R-T-B systems sintered magnet is with excellent magnetic characteristic, due to containing easily by oxygen as main component The rare earth element of change, therefore it is low to tend to corrosion resistance.

Used R-T-B systems sintered magnet can aoxidize R-T- due to the water of the vapor in use environment etc. all the time R in B systems sintered magnet and produce hydrogen, the R enrichment phases in crystal boundary absorb the hydrogen, are carried out so as to the corrosion of R enrichment phases, R-T-B It is the magnetic characteristic reduction of sintered magnet.

In order to improve the corrosion resistance of R-T-B systems sintered magnet, generally implement resin on the ferritic surface of magnetic mostly Coating or the surface treatment of coating etc. use.On the other hand, also carry out by changing the ferritic addition element of magnetic or inside Structure is improved the corrosion resistance of magnet ferritic in itself.The corrosion resistance of magnet ferritic in itself is improved to improve at surface It is of crucial importance in terms of the reliability of product after reason, in addition, thereby, it is possible to implement than resin coating or the more easy surface of coating Processing, so as to also have the advantages of cost that can reduce product.

All the time, for example, being proposed in patent document 1：By the way that the carbon content in permanent magnetic alloy is reduced to Below 0.04 mass %, so as to which the rare earth element in non magnetic R enrichment phases and the intermetallic compound R-C of carbon are suppressed into 1.0 Below quality %, and the technology for improving the corrosion resistance of magnet.In addition, proposed in patent document 2：By being enriched with R Co concentration in phase is the mass % of 5 mass %~12, so as to improve the technology of corrosion resistance.

However, as proposed in patent document 1, in order to which the carbon content in coupernick is reduced into 0.04 matter Measure below % and be necessary to be greatly reduced lubrication when shaping in magnetic field for improving magnetic field orientating and adding The addition of agent.Therefore, the degree of orientation of the magnetic in formed body is reduced, and the residual magnetic flux density Br after sintering is reduced, from And the magnet with sufficient magnetic characteristic can not be obtained.

In addition, as proposed in patent document 2, original is necessarily increased in order to increase the Co concentration in R enrichment phases Expect the Co additions of composition.But because Co is that the R as principal phase is also entered in the form of substituting Fe₂T₁₄B phases, so not The Co concentration of R enrichment phases can only be increased, and need to add the Co more than needed for R enrichment phases.Therefore, because the Co of increase high price Usage amount and product cost is increased, and because necessary amount with Shangdi instead of Fe in principal phase so as to which magnetic characteristic drops with Co It is low.

Prior art literature

Patent document

Patent document 1：Japanese Unexamined Patent Publication 4-330702 publications

Patent document 2：Japanese Unexamined Patent Publication 4-6806 publications

The content of the invention

The technical problems to be solved by the invention

The present invention in view of the foregoing, its object is to provide it is a kind of there is excellent corrosion resistance, and have concurrently well Magnetic characteristic R-T-B systems sintered magnet and possess its motor.

Solves the technological means of technical problem

In order to reach above-mentioned purpose, the mechanism of corrosion of the present inventors to R-T-B systems sintered magnet attentively grind Study carefully.Its result understands, the corrosion of R-T-B systems sintered magnet passes through the water and R-T-B that are brought by vapor under use environment etc. Hydrogen caused by being the corrosion reaction of the R generations in sintered magnet, which is adsorbed in the crystal boundary in R-T-B systems sintered magnet, to be deposited R enrichment phases and develop.

If illustrating details, it is considered that the corrosion of R-T-B systems sintered magnet is carried out with process as described below. Firstly, because the R enrichment phases for being present in crystal boundary are oxidized easily, so the R for the R enrichment phases being present in crystal boundary is by use environment Under the water oxygenization brought such as vapor so as to which R is corroded, be changed into hydroxide, and produce hydrogen in this process.

2R+6H₂O→2R(OH)₃+3H₂ (I)

Then, the caused hydrogen is adsorbed in the R enrichment phases not being corroded.

2R+xH₂→2RHx (II)

Then, by hydrogen absorption so as to which R enrichment phases become easier to be corroded, and the adsorbed R enrichment phases of hydrogen are passed through The corrosion reaction occurred with water is so as to and generate the hydrogen being adsorbed on more than the amount of R enrichment phases.

2RHx+6H₂O→2R(OH)₃+(3+x)H₂ (III)

Magnetic is sintered to R-T-B systems so as to the corrosion of R-T-B systems sintered magnet by above-mentioned (I)~(III) chain reaction The inside progress of iron, R enrichment phase changes are R hydroxide, R hydride.Put aside by the volumetric expansion with the change Stress, so that forming the R of the principal phase of R-T-B systems sintered magnet₂T₁₄B crystal grain (principal phase particle) is fallen off.Then, pass through The coming off for crystal grain of principal phase and there is the face of the new formation of R-T-B systems sintered magnet.The face newly formed again with use environment Vapor etc. react, above-mentioned (I)~(III) chain reaction occurs, so as to produce the face newly formed again.By this Circulation is so as to the corrosion further in-house development to R-T-B systems sintered magnet of R-T-B systems sintered magnet.

Therefore, the present inventors have carried out wholwe-hearted research to the method for suppressing the development of the corrosion of crystal boundary, find：By R- R more than adjacent 2 in T-B systems sintered magnet₂T₁₄The crystal boundary that B crystal grain is formed is (particularly by adjacent more than 3 R₂T₁₄The trident crystal boundary that B crystal grain is formed) in formed R (R at least one kind of in rare earth element), Cu, M (M be selected from Ga, It is at least one kind of in Si, Sn, Ge, Bi) and C concentration be all higher than R₂T₁₄R-Cu-M-C concentrating part in B crystal grain, so as to Suppress hydrogen and be adsorbed in crystal boundary, the corrosion resistance of R-T-B systems sintered magnet can be significantly increased, and can have well Magnetic characteristic.The present invention is namely based on what above-mentioned discovery was completed.

That is, R-T-B systems sintered magnet involved in the present invention, it is characterised in that the R-T-B systems sintered magnet has R₂T₁₄B crystal grain, by the adjacent above-mentioned R of more than 2₂T₁₄The crystal boundary portion that B crystal grain is formed has R-Cu-M-C concentrating part, compares Above-mentioned R₂T₁₄The R (R at least one kind of in rare earth element) of above-mentioned R-Cu-M-C concentrating part in B crystal grain, Cu, M (M be selected from It is at least one kind of in Ga, Si, Sn, Ge, Bi) and C concentration it is all higher.

In the section of above-mentioned R-T-B systems sintered magnet, above-mentioned R-Cu-M-C concentrating part face shared in above-mentioned crystal boundary Product is preferably more than 1%.

Further in addition, Cu and M atoms is total relative to the ratio between whole R atomicities in above-mentioned R-Cu-M-C concentrating part (Cu+M)/R is preferably more than 0.2 and less than 0.6.

In the present invention, by R-Cu-M-C concentrating part in crystal boundary be present, can effectively suppress to produce in corrosion reaction Raw hydrogen is adsorbed on the R enrichment phases present in crystal boundary, and the corrosion resistant of R-T-B systems sintered magnet can be significantly increased Corrosion.Further, the formation of the R-Cu-M-C concentrating part hardly has an impact to magnetic characteristic, can keep good magnetic spy Property.In addition, although R enrichment phases, which are defined as R, compares R₂T₁₄B crystal grain is more, but at least C in Cu, M, C containing only with R₂T₁₄B The Grain-Boundary Phase of crystal grain degree following on an equal basis.

The present invention further provides the motor for the R-T-B systems sintered magnet for possessing the invention described above.The present invention's is electronic Machine is due to possessing the R-T-B systems sintered magnet of the invention described above, therefore, is used under conditions of high humility etc. is harsh, by Corrode caused by the generation of the rust as R-T-B systems sintered magnet etc. less, accordingly it is also possible to play excellent performance for a long time.

The effect of the present invention

According to the present invention it is possible to obtain that there is excellent corrosion resistance, and the R-T-B systems for having good magnetic characteristic concurrently burn Tie magnet.In addition, according to the present invention it is possible to provide a kind of motor, its by possessing such R-T-B systems sintered magnet, from And it can also maintain excellent performance for a long time under hot and humid environment.

Brief description of the drawings

Fig. 1 be show schematically R-T-B systems sintered magnet involved in the present invention by multiple R₂T₁₄The crystalline substance that B crystal grain is formed Figure near boundary.

Fig. 2 is the flow chart for representing to manufacture an example of the method for R-T-B systems sintered magnet involved in the present invention.

Fig. 3 is the sectional view of the composition for an embodiment for being schematically indicated motor.

Fig. 4 is enlarged drawing (10 μ ms of Nd surveying and mapping data in the R-T-B systems sintered magnet section for represent embodiment 2 10μm)。

Fig. 5 is enlarged drawing (10 μ ms of Pr surveying and mapping data in the R-T-B systems sintered magnet section for represent embodiment 2 10μm)。

Fig. 6 is enlarged drawing (10 μ ms of Cu surveying and mapping data in the R-T-B systems sintered magnet section for represent embodiment 2 10μm)。

Fig. 7 is enlarged drawing (10 μ ms of Ga surveying and mapping data in the R-T-B systems sintered magnet section for represent embodiment 2 10μm)。

Fig. 8 is enlarged drawing (10 μ ms 10 of C surveying and mapping data in the R-T-B systems sintered magnet section for represent embodiment 2 μm)。

Fig. 9 is that the concentration distribution of R, Cu, M, C each element in the R-T-B systems sintered magnet section for represent embodiment 2 is high In the figure of an example in the region (R-Cu-M-C concentrating part) in the crystal grain of principal phase.

Symbol description

2 particles (principal phase)

4 two particle crystal boundaries

6 trident crystal boundaries

10 SPM motor

11 housings

12 rotors

13 stators

14 rotary shafts

15 rotor cores (iron core)

16 permanent magnets

17 magnet insertion grooves

18 stator cores

19 choke valves

20 coils

Embodiment

The embodiment of the R-T-B systems sintered magnet of the present invention is illustrated below.

<R-T-B systems sintered magnet>

R-T-B systems sintered magnet involved by present embodiment is that (R is represented in rare earth element extremely using R-T-B Few a kind, T represents to include Fe or more than a kind of the transition metal comprising Fe and Co, and B represents B or represents B and C) system The sintered body that alloy is formed.As shown in figure 1, the R-T-B systems sintered magnet involved by present embodiment has by R₂T₁₄B crystal grain The particle (principal phase) 2 of composition, there is R-Cu-M-C concentrating part in the crystal boundary formed by the adjacent particle 2 of more than 2, compare Above-mentioned R₂T₁₄In B crystal grain, R, Cu, M, C of the R-Cu-M-C concentrating part concentration are all higher.Crystal boundary is included by 2 R₂T₁₄B crystal grain Formed two particle crystal boundaries 4, by the adjacent R of more than 3₂T₁₄The trident crystal boundary 6 (polycrystalline boundaries portion) that B crystal grain is formed.

By above-mentioned R₂T₁₄The particle (principal phase) that B crystal grain is formed has by R₂T₁₄The crystalline texture that the tetragonal of Type B is formed.Separately Outside, R₂T₁₄The average grain diameter of B crystal grain is usually 1 μm~30 μm or so.

Included in above-mentioned crystal boundary and compare above-mentioned R₂T₁₄R (R is at least one kind of in rare earth element), Cu, M in B crystal grain The all higher R-Cu-M-C concentrating part of (M is at least one kind of in Ga, Si, Sn, Ge, Bi) and C concentration is compared R₂T₁₄The more R enrichment phases of B crystal grain R.In addition, can also contain boron (B) atom mixing ratio it is high B enrichment it is equal its Its phase.As long as comprising R, Cu, M, C as main component in R-Cu-M-C concentrating part, it is possible to include the composition beyond these.

The R of R-T-B systems sintered magnet involved by present embodiment represents at least one kind of in rare earth element.Rare earth Element refers to Sc, the Y and lanthanide series for belonging to the 3rd race of long period type periodic table.Lanthanide series include La, Ce, Pr, Nd、Sm、Eu、Gd、Tb、Dy、Ho、Er、Tm、Yb、Lu.Rare earth element is classified as light rare earth class and heavy rare earth class, heavy rare earth member Plain (hereinafter also referred to RH) refers to Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, LREE (hereinafter also referred to RL) be except this with Outer rare earth element.In the present embodiment, from the viewpoint of manufacturing cost and magnetic characteristic, R preferably comprises RL and (at least wrapped Containing Nd, Pr any one or both rare earth element).Further from the viewpoint of magnetic characteristic raising is made, it can also include RL (rare earth element for comprising at least any one of Nd, Pr or both) and RH (comprise at least any one of Dy, Tb or both Rare earth element) both.

The T of R-T-B systems sintered magnet involved by present embodiment represents more than a kind comprising Fe or comprising Fe and Co Transition metal.T can be individually for Fe, can also substitute a part of Fe with Co.As the transition metal beyond Fe and Co Element, Ti, V, Cu, Cr, Mn, Ni, Zr, Nb, Mo, Hf, Ta, W etc. can be enumerated.In addition, T is in addition to transition metal At least one kind of element in the element such as Al, Ga, Si, Bi, Sn can further be included.

The B of R-T-B systems sintered magnet involved by present embodiment represents boron, and a part of B can be substituted by carbon (C). In this case, in addition to the manufacture for making magnet becomes easily, additionally it is possible to realize the reduction of manufacturing cost.In addition, C substitution Measure not influence the amount of magnetic characteristic substantially.

In addition, it in addition can also inevitably be mixed into O, Ca etc..These can also be to be respectively 0.5 mass % journeys Amount below spending contains.

The content of the R in R-T-B systems sintered magnet involved by present embodiment is more than 25 mass % and 35 mass % Hereinafter, preferably more than 29.5 mass % and below 33 mass %, more preferably more than 29.5 mass % and 32 mass % Below.When R content is less than 25 mass %, turn into the R of R-T-B systems sintered magnet principal phase₂T₁₄The generation of B compounds is not Fully.Therefore, α-Fe with soft magnetism etc. are separated out, magnetic characteristic is likely to decrease.In addition, if R content is more than 35 matter % is measured, then as the R of R-T-B systems sintered magnet principal phase₂T₁₄The volume ratio of B compounds is reduced, and magnetic characteristic is likely to decrease, separately Outside, corrosion resistance reduction is also tended to.

The content of the B in R-T-B systems sintered magnet involved by present embodiment is more than 0.5 mass % and 1.5 matter Measure below %, preferably more than 0.7 mass % and below 1.2 mass %, more preferred B amount for more than 0.75 mass % and Below 0.95 mass %.If B content is less than 0.5 mass %, there are coercivity H J reductions.In addition, if B Content then has the tendency of residual magnetic flux density Br reductions more than 1.5 mass %.Particularly, B content is more than 0.75 mass % And when in 0.95 scope below mass %, become easily to form R-Cu-M-C concentrating part.

As described above, the T in R-T-B systems sintered magnet involved by present embodiment represent comprising Fe or comprising Fe and Co more than a kind of transition metal.Fe content is R-T-B in R-T-B systems sintered magnet involved by present embodiment Be sintered magnet inscape in substantial surplus, a part of Fe can also be substituted with Co.Co content is preferably More than 0.3 mass % and below 3.0 mass % scope, more preferably more than 1.0 mass % and below 2.0 mass %. If Co content has the tendency of residual magnetic flux density reduction, in addition, there is raw material cost to become costliness more than 3.0 mass % Tendency.In addition, if Co content is less than 0.3 mass %, then tend to corrosion resistance reduction.Beyond Fe or Fe and Co Transition metal, Ti, V, Cr, Mn, Ni, Cu, Zr, Nb, Mo, Hf, Ta, W etc. can be enumerated.In addition, T is except transition metal Can also be further comprising at least one kind of element in the element such as Al, Ga, Si, Bi, Sn beyond element.

Cu is included in the R-T-B systems sintered magnet of present embodiment.Cu content is preferably 0.01~1.5 mass %, is entered One step is preferably 0.05~1.0 mass %, more preferably 0.05~0.55 mass %.By containing Cu, obtained magnet energy Enough high-coercive forces, highly corrosion resistant, improve temperature characterisitic.If Cu content has residual flux more than 1.5 mass % The tendency that density reduces.In addition, if Cu content is less than 0.01 mass %, then it is difficult to form R-Cu-M-C concentrating part, is inclined to Reduced in corrosion resistance.Especially, in Cu content more than 0.05 mass % and during below 0.55 mass % scope, become Easily form R-Cu-M-C concentrating part.

Comprising M, (M is more than a kind in Ga, Si, Sn, Ge, Bi in the R-T-B systems sintered magnet of present embodiment Element).M content is preferably 0.01~1.5 mass %, more preferably 0.05~1.0 mass %.It is especially excellent as M Elect Ga as.By containing M, obtained magnet being capable of high-coercive force, highly corrosion resistant, improvement temperature characterisitic.It is particularly logical Cross containing M formed R-Cu-M-C concentrating part, so as to improve corrosion resistance.If M content more than 1.5 mass %, There is residual magnetic flux density reduction.In addition, if M content is less than 0.01 mass %, then it is difficult to form R-Cu-M-C dense Contracting portion, it is intended to which corrosion resistance reduces.

The R-T-B systems sintered magnet of present embodiment preferably comprises Al.By containing Al, obtained magnet being capable of high coercive Power, highly corrosion resistant, improve temperature characterisitic.Al content is preferably more than 0.03 mass % and below 0.6 mass %, enters One step is preferably more than 0.05 mass % and below 0.25 mass %.

In the R-T-B systems sintered magnet of present embodiment, Zr can also be contained as needed., can be with by containing Zr Suppress grain growth during sintering, improve sintering temperature amplitude.In the case of containing Zr, Zr content is preferably 0.01 matter Measure more than % and below 1.5 mass %.

R-T-B systems sintered magnet involved by present embodiment can also include a certain amount of oxygen (O).It is a certain amount of according to it Its parameter etc. changes and suitably determined, from the viewpoint of corrosion resistance, oxygen amount is preferably more than 500ppm, from magnetic characteristic From the viewpoint of, preferably below 2500ppm, more preferably below 2000ppm.

In addition, can also include nitrogen (N) in R-T-B systems sintered magnet involved by present embodiment, the nitrogen quantity is according to it Its parameter etc. changes and suitably determined, but if nitrogen quantity increases, then magnetic characteristic reduces.

In addition, the R-T-B systems sintered magnet involved by present embodiment includes carbon (C).Carbon amounts is 100~2000ppm, excellent Elect 200~1500ppm, particularly preferably 500~1500ppm as.The adding method of carbon (C) in R-T-B systems sintered magnet does not have Have and especially limit, can be added in the way of the manufacturing process of sintered body as carbon or carbon compound, can also be in diffusion materials It is imported into material containing carbon from sintered body surface in crystal boundary.

The assay method of oxygen amount, carbon amounts, nitrogen quantity in R-T-B systems sintered magnet can use existing commonly known side Method.Oxygen amount can be measured for example, by inert gas fusion-non-dispersive type infrared absorption, and carbon amounts can pass through example As burning-infrared absorption is measured in oxygen stream, nitrogen quantity can enter for example, by inert gas fusion-thermal conductivity method Row measure.

As described above, the R-T-B systems sintered magnet involved by present embodiment has in crystal boundary compares R₂T₁₄In B crystal grain R, all higher R-Cu-M-C concentrating part of Cu, M, C concentration.Because the concentrating part is difficult to adsorb hydrogen, therefore, it is possible to prevent by corruption Erosion is reacted and caused hydrogen is adsorbed to the R enrichment phases of inside, and can be suppressed corrosion and be internally in progress.Further, since R- Cu-M-C concentrating part is difficult to be oxidized compared with R enrichment phases, accordingly it is also possible to suppress because hydrogen caused by corrosion produces this Body.Therefore, it is possible to which the corrosion resistance of R-T-B systems sintered magnet is significantly increased.In addition, the R-Cu-M-C concentrating part in crystal boundary Influence of the formation to magnetic characteristic it is small, so as to keep the magnetic characteristic of R-T-B systems sintered magnet well.

In the present embodiment, in the section of R-T-B systems sintered magnet, above-mentioned R-Cu-M-C concentrating part institute in crystal boundary The area accounted for is preferably more than 1%.The method of trying to achieve of area illustrates later.If the area mistake of R-Cu-M-C concentrating part Small, then tending to the effect of corrosion resistance improvement reduces.

Further, in the present embodiment, in R-Cu-M-C concentrating part Cu atomicities and M atomicities it is total relative to complete The ratio between portion's R atomicities (Cu+M)/R is preferably more than 0.2 and less than 0.6.Even if form deviate the scope R-Cu-M-C it is dense Contracting portion, it may have the effect that corrosion resistance improves, it is believed that R-Cu-M-C concentrating part in order to improve corrosion resistance and Particularly suitable composition be present, if the scope, then effect is especially high.

Further, preferable C concentration is 3~30 atom % in the R-Cu-M-C concentrating part of present embodiment, further Preferably 9~20 atom %.

As described later, the R-T-B systems sintered magnet involved by present embodiment can be by except primarily forming principal phase Beyond R-T-B systems raw alloy (the 1st alloy), also addition primarily forms the 2-in-1 gold of Grain-Boundary Phase, and controls in manufacturing process The manufacturing condition of heat treatment condition etc. manufactured.Groups of elements for forming R-Cu-M-C concentrating part can be in alloy system The either phase addition make, crushed.Alternatively, it is also possible to be imported into using grain boundary decision method from sintered body surface in crystal boundary.

R-Cu-M-C concentrating part formed in the crystal boundary of R-T-B systems sintered magnet involved by present embodiment can recognize It is R, Cu, M present in the 2-in-1 gold (M is at least one kind of in Ga, Si, Sn, Ge, Bi) and carbon in sintering or timeliness etc. Compound is formed in heat treatment step, is appeared in the form of R-Cu-M-C concentrating part in crystal boundary.Be free of in 2-in-1 gold There are Cu, M, carbon, these elements can also be imported into crystal boundary after sintering circuit with grain boundary decision the methods of.Now, may be used It is weight to think fit to be diffused formation of the heat treatment after heat treatment or diffusion heat treatments for R-Cu-M-C concentrating part Want.

R-T-B systems sintered magnet involved by present embodiment can generally be processed into arbitrary shape to use.To this The shape of R-T-B systems sintered magnet involved by embodiment is not particularly limited, such as cuboid, six faces can be made The columns such as body, tabular, quadrangular, the cross sectional shape of R-T-B systems sintered magnet is the arbitrary shapes such as the cylindrical shape of c-type.Make For quadrangular, such as it can be the quadrangular that bottom surface is rectangular quadrangular, bottom surface is square.

In addition, the R-T-B systems sintered magnet involved by present embodiment includes processing the magnet and carried out magnetized Magnet product, both magnetized magnet products are not carried out to the magnet.

There is using accompanying drawing and just the manufacture of the R-T-B systems sintered magnet involved by the present embodiment of structure as described above One example of method illustrates.Fig. 2 is to represent to manufacture the R-T-B systems sintered magnet involved by embodiments of the present invention The flow chart of one example of method.As shown in Fig. 2 the method for the R-T-B systems sintered magnet involved by manufacture present embodiment With following process.

(a) the 1st alloy and 2-in-1 golden alloy preparatory process (step S11) are prepared

(b) alloy of flour the 1st and 2-in-1 golden pulverizing process (step S12)

(c) mixed processes (step S13) of the 1st alloy powder and 2-in-1 bronze end are mixed

(d) molding procedure (step S14) being molded to mixed mixed-powder

(e) sintered moulded body, the sintering circuit (step S15) of R-T-B systems sintered magnet is obtained

(f) ageing treatment process (step S16) of Ageing Treatment is carried out to R-T-B systems sintered magnet

(g) refrigerating work procedure (step S17) of R-T-B systems sintered magnet is cooled down

(h) manufacturing procedure (step S18) being processed to R-T-B systems sintered magnet

(i) the grain boundary decision process (step S19) that rare earth element etc. is spread in the crystal boundary of R-T-B systems sintered magnet is made

(j) surface treatment procedure (step S20) being surface-treated to R-T-B systems sintered magnet

[alloy preparatory process：Step S11]

Prepare alloy (the 1st conjunction of the composition of main composition principal phase in the R-T-B systems sintered magnet involved by present embodiment Gold) and composition crystal boundary composition alloy (2-in-1 gold) (alloy preparatory process (step S11)).In alloy preparatory process (step S11 in), melting is corresponding to the R- involved by present embodiment in the inert gas atmosphere of the inert gas such as vacuum or Ar gas The feed metal of the composition of T-B systems sintered magnet, then, cast by using it so as to produce with desired The 1st alloy and 2-in-1 gold of composition.In addition, in the present embodiment, for the 1st alloy of mixing and this 2-in-1 golden 2 kinds of alloys Illustrated to make the situation of two alloyages of material powder but it is also possible to be regardless of the 1st alloy and 2-in-1 gold and using single Single alloyage of only alloy.

As feed metal, for example, can use rare earth metal or rare earth alloy, pure iron, ferro-boron (ferroboron), Even these alloy or compound etc..The casting method of cast raw material metal, such as ingot bar casting, thin strap continuous casting method (strip casting method), book mold method (book molding method) or centre spinning etc..What is obtained In the case that raw alloy has solidifying segregation, homogenize process is carried out as needed.Carrying out the homogenize process of raw alloy When, keep coming in fact for more than 1 hour with more than 700 DEG C and less than 1500 DEG C of temperature under vacuum or inert gas atmosphere OK.Thus, R-T-B systems sintered magnet is melted with alloy homogenizes.

[pulverizing process：Step S12]

After the 1st alloy and 2-in-1 gold has been made, the 1st alloy and 2-in-1 golden (pulverizing process (step are crushed S12)).In pulverizing process (step S12), after the 1st alloy and 2-in-1 gold has been made, these the 1st conjunctions are crushed respectively Gold and 2-in-1 gold, are made powder.It is inclined from control composition alternatively, it is also possible to which the 1st alloy and 2-in-1 gold are crushed together From viewpoint etc. set out, more preferably crushed respectively.

Pulverizing process (step S12), which has, is crushed to coarse crushing process (step of the particle diameter as hundreds of μm~number mm degree S12-1) and micro mist is broken to Crushing of Ultrafine process (step S12-2) of the particle diameter as several μm of degree.

(coarse crushing process：Step S12-1)

1st alloy and 2-in-1 golden coarse powder are broken to degree (coarse crushing process of the respective particle diameter as hundreds of μm~number mm (step S12-1)).Thus, the 1st alloy and 2-in-1 golden coarse powder comminuted powder are obtained.Coarse crushing can be by adsorbing hydrogen The difference based on the hydrogen adsorptive capacity between different phases puts hydrogen release and carries out dehydrogenation so as to send out after the 1st alloy and 2-in-1 gold It is born from collapsibility and crushes (hydrogen absorption crushes) to carry out.In addition, in order to promote to be formed R-Cu-M-C concentrating part, can also be in coarse powder C is mixed in flour, is heat-treated under 500~900 DEG C of temperature province.

, can also be in addition to being crushed as described above using hydrogen absorption in addition, coarse crushing process (step S12-1) Stamping mill (stamp mill), jaw crusher (jaw crusher), Blang's pulverizer (Braun are used in inert gas atmosphere ) etc. mill Roughpulverizer is carried out.

In addition, in order to obtain high magnetic characteristic, from pulverizing process (step S12) to each work of sintering circuit (step S15) The atmosphere of sequence is preferably made to low oxygen concentration.Oxygen concentration is adjusted by control of the atmosphere in each manufacturing process etc..Such as The oxygen concentration of each manufacturing process of fruit is high, then the rare earth element in the 1st alloy and 2-in-1 golden powder occurs to aoxidize and generate R oxides, directly separated out in sintering in the form of the R oxides not being reduced in crystal boundary, and obtained R-T-B systems burn Tying the Br of magnet reduces.Thus, for example, it is preferred to the concentration for making the oxygen of each process is below 100ppm.

(Crushing of Ultrafine process：Step S12-2)

After coarse crushing is carried out to the 1st alloy and 2-in-1 gold, by the 1st obtained alloy and 2-in-1 golden coarse crushing Powder micro mist, which is broken to average grain diameter, turns into several μm of degree (Crushing of Ultrafine process (step S12-2)).Thus, the 1st alloy and the 2nd are obtained The micro mist comminuted powder of alloy.By the way that the further Crushing of Ultrafine of coarse powder pulverized powder will be passed through, so as to obtain that there is preferably 1 μm Above and less than 10 μm, more preferably more than 3 μm and less than 5 μm of particle micro mist comminuted powder.

In addition, enter in a manner of obtaining micro mist comminuted powder to crush the 1st alloy and 2-in-1 gold respectively in the present embodiment OK, but can also be mixed in Crushing of Ultrafine process (step S12-2) the 1st alloy and 2-in-1 golden coarse powder comminuted powder from And the mode for obtaining micro mist comminuted powder is carried out.

Crushing of Ultrafine can suitably adjust the conditions such as grinding time by one side, while using airflow milling, ball mill, vibration The atomizers such as mill, wet grinding machine by coarse powder pulverized powder to carrying out further crush to implement.Airflow milling is to pass through Narrow and small nozzle discharges high-pressure inert gas (for example, N₂Gas or Ar gas etc.) high velocity air is produced, accelerated by the high velocity air 1st alloy and 2-in-1 golden coarse powder comminuted powder simultaneously make the 1st alloy and 2-in-1 golden coarse powder comminuted powder collide each other Or the method for making it collide to be crushed with object or chamber wall.

When the 2-in-1 golden coarse powder comminuted powder of the alloy of Crushing of Ultrafine the 1st and, by adding zinc stearate, oleic acid acyl The grinding aids such as amine, so as to obtain the high micro mist comminuted powder of orientation in shaping.It is in addition, dense in order to form R-Cu-M-C Contracting portion, these grinding aid can be used to use other carbon sources as carbon source.Or can also be in the process Do not add for forming the carbon component of R-Cu-M-C concentrating part and sintered in grain boundary decision process described later in R-T-B based magnets Carbon is imported in vivo.

[mixed processes：Step S13]

After the alloy of Crushing of Ultrafine the 1st and 2-in-1 gold, each micro mist comminuted powder (mixed processes (step is mixed in hypoxic atmosphere Rapid S13)).Thus, it is possible to obtain mixed-powder.Hypoxic atmosphere is for example formed as N₂The inert gas atmospheres such as gas, Ar gas atmosphere. The compounding ratio at the 1st alloy powder and the 2-in-1 bronze end is preferably more than 80 to 20 by quality ratio and less than 97 to 3, more It is preferred that it is more than 90 to 10 and less than 97 to 3 by quality ratio.

In addition, in pulverizing process (step S12), matching somebody with somebody in the case that the 1st alloy and 2-in-1 gold are crushed together Composition and division in a proportion rate is also identical with the situation for being crushed the 1st alloy and 2-in-1 gold respectively, the 1st alloy powder and the 2-in-1 bronze end Compounding ratio is preferably by quality ratio more than 80 to 20 and less than 97 to 3, more preferably by quality ratio to be more than 90 to 10 and Below 97 to 3.

In the present embodiment, the 1st alloy and the preferably mutual alloy of 2-in-1 gold form different.For example, compared to the 1st Alloy, 2-in-1 gold more include M, Cu.

Total quality % of M in the 2-in-1 gold more than contained 1 in Ga, Si, Sn, Ge, Bi kind is preferably 0.2%~20%, more preferably 0.5%~10%.1st alloy can include M, can also not include M, in the 1st alloy In include M in the case of, contained M total quality % is preferably less than 0.2% in the 1st alloy.Contained by 2-in-1 gold Cu quality % is preferably 0.2%~20%, and more preferably 0.5%~10%.1st alloy can include Cu, can also Not comprising Cu, in the case of including Cu in the 1st alloy, contained Cu quality % is preferably less than 0.2% in the 1st alloy.

[molding procedure：Step S14]

After the 1st alloy powder and 2-in-1 bronze end is mixed, mixed-powder is shaped to target shape (molding procedure (step S14)).In molding procedure (step S14), by the way that the mixed-powder of the 1st alloy powder and 2-in-1 bronze end is filled Fill in the mould wrapped up by electromagnet and pressurizeed, so as to which mixed-powder is shaped into arbitrary shape.Now, while applying Add magnetic field while being molded, by applying magnetic field so that material powder produces defined orientation, so that what crystal axis was orientated State is molded in magnetic field.It is hereby achieved that formed body.Because obtained formed body is orientated in prescribed direction, so can obtain To with the stronger anisotropic R-T-B systems sintered magnet of magnetic.

Pressurization during shaping is preferably carried out under 30MPa~300MPa.The magnetic field of application be preferably 950kA/m~ 1600kA/m.The magnetic field of application is not limited to magnetostatic field, or pulse type magnetic field.Alternatively, it is also possible to and with magnetostatic field and Pulse type magnetic field.

In addition, as forming method except as described above by mixed-powder straight forming it is dry formed in addition to, can also It is applicable to material powder will be made to be scattered in the wet type shaping that slurry resulting in oily equal solvent is molded.

The shape of formed body obtained from mixed-powder is molded is not particularly limited, such as can be cuboid, flat Arbitrary shape is made according to the shape of desired R-T-B systems sintered magnet in tabular, column, ring-type etc..

[sintering circuit：Step S15]

It is molded in magnetic field, sinter molding is shaping obtained from target shape in vacuum or inert gas atmosphere Body, obtain R-T-B systems sintered magnet (sintering circuit (step S15)).Sintering temperature is needed according to composition, breaking method, granularity It is adjusted with all condition such as the difference of size distribution, but for formed body for example by a vacuum or in inertia The processing that heating more than 1 hour and less than 48 hours is carried out with more than 1000 DEG C and less than 1200 DEG C in the presence of gas are burnt Knot.Thus, liquid-phase sintering occurs for mixed-powder, obtains the R-T-B systems sintered magnet (R-T-B that the volume ratio of principal phase improves The sintered body of based magnet).After formed body has been sintered, from the viewpoint of production efficiency is improved, preferred pair sintered body enters Row chilling.In addition, before sintering circuit import carbon source in the case of, by the temperature-rise period of sintering at 500~700 DEG C Temperature province in stabilizers are set, or slowly heat up, so as to generate the liquid phase of the M comprising terres rares, Cu and Ga etc. And reacted with the carbon of importing, and form R-Cu-M-C concentrating part.Especially, carry out what hydrogen absorption crushed in coarse crushing process In the case of, it can cause dehydrogenation reaction by being heat-treated as progress, therefore, further promote the shape of R-Cu-M-C concentrating part Into.

[ageing treatment process：Step S16]

After formed body has been sintered, Ageing Treatment (ageing treatment process (step is carried out to R-T-B systems sintered magnet S16)).After burning till, by less than sintering when temperature under conditions of keep resulting R-T-B systems sintered magnet etc. come pair R-T-B systems sintered magnet implements Ageing Treatment.Ageing Treatment heats 10 for example more than 700 DEG C and at less than 900 DEG C of temperature 2 stepwise heatings of 10 minutes to 6 hours minute by 6 hours and are further heated at a temperature of 500 DEG C to 700 DEG C, at 600 DEG C 10 minutes to 6 hours 1 stepwise heating etc. is heated at neighbouring temperature, it is suitable to adjust according to the number for implementing Ageing Treatment Treatment conditions.Pass through such Ageing Treatment, it is possible to increase the magnetic characteristic of R-T-B systems sintered magnet.In addition, ageing treatment process (step S16) can also be carried out after manufacturing procedure (step S18) or grain boundary decision process (step S19).

[refrigerating work procedure：Step S17]

After Wetted constructures are implemented to R-T-B systems sintered magnet, R-T-B systems sintered magnet is entered in Ar gas atmosphere Row chilling (refrigerating work procedure (step S17)).Thereby, it is possible to obtain the R-T-B systems sintered magnet involved by present embodiment.Cooling Speed is not particularly limited, and is preferably set to 30 DEG C/more than min.

[manufacturing procedure：Step S18]

Obtained R-T-B systems sintered magnet can also be processed into desired shape (manufacturing procedure as needed：Step S18).Processing method shape such as can enumerate cut-out, grinding is processed, chamfer machining such as roller grinding etc..

[grain boundary decision process：Step S19]

There can also be the crystal boundary to the R-T-B systems sintered magnet after processing, be imported by grain boundary decision for forming R- R, Cu, M, C of Cu-M-C concentrating part process (grain boundary decision process：Step S19).Grain boundary decision can contain example by making Alloy powder such as R, Cu, M is allowed to be attached to R-T-B systems sintered magnet, and is heat-treated to implement.Or it can pass through Evaporation etc. makes each element be attached to the surface of R-T-B systems sintered magnet and is heat-treated to implement.In addition, for example, due to such as Fruit contains carbon as the composition of the alloy powder of diffusion component, then can import R, Cu, M and C into crystal boundary simultaneously, therefore, It is effective for formation R-Cu-M-C concentrating part.Further, in order to further improve the coercive of R-T-B systems sintered magnet Power, the heavy rare earth elements such as Dy, Tb can also be contained in part or all of the R of diffusion element.It is heat-treated in grain boundary decision Afterwards, the heat treatment for forming R-Cu-M-C concentrating part can also suitably be added.It is terrible in the last of grain boundary decision process To good magnetic characteristic, the aging strengthening model of 0.5~5 hour or so can also be nearby carried out at 500~600 DEG C.

[surface treatment procedure：Step S20]

The obtained R-T-B systems sintered magnet of process more than can also implement coating or resin coating, oxidation processes, blunt The surface treatment (surface treatment procedure (step S20)) of change processing etc..Thereby, it is possible to further improve corrosion resistance.

In addition, in the present embodiment, carry out manufacturing procedure (step S18), grain boundary decision process (step S19), surface Treatment process (step S20), but these each operations are not necessarily necessary to carry out.

The R-T-B systems sintered magnet involved by present embodiment, end processing is so made.In addition, by being allowed to magnetize So as to obtain magnet product.

R-T-B systems sintered magnet involved by thus obtained present embodiment in crystal boundary due to having R-Cu-M-C dense Contracting portion, therefore, there is excellent corrosion resistance, and there is good magnetic characteristic.

R-T-B systems sintered magnet involved by the present embodiment so obtained is in the magnetic for whirlers such as motor In the case of iron, because corrosion resistance is high can be long-term use of, and the high R-T-B systems of reliability can be obtained and sinter magnetic Iron.R-T-B systems sintered magnet involved by present embodiment for example can suitably be used as being provided with magnet in rotor surface Surface permanent magnetic type (Surface Permanent Magnet：SPM) motor, as the brushless motor of inner-rotor type Built-in type permanent-magnet type (Interior Permanent Magnet：IPM) motor, PRM (permanent magnet reluctance motor, Permanent magnet Reluctance Motor) etc. magnet.Specifically, the R-T-B systems involved by present embodiment burn Tie magnet can suitably as hard disk drive hard disk rotation driving spindle drive motor or voice coil motor, electric car or Hybrid Vehicle motor, the motor for electric power steering of automobile, the servomotor of work mechanism (servomotor), the purposes such as the vibrator motor of mobile phone, printing machine motor, generator motor.

<Motor>

Then, to by the R-T-B systems sintered magnet involved by present embodiment be used for motor preferred embodiment Illustrate.A here, example for the R-T-B systems sintered magnet involved by present embodiment to be applied to SPM motor Son illustrates.Fig. 3 is the sectional view of the composition for an embodiment for being schematically indicated SPM motor, as shown in figure 3, SPM Motor 10 is in housing 11 with columned rotor 12, cylindric stator 13 and rotary shaft 14.The insertion of rotary shaft 14 turns The center of the cross section of son 12.

Rotor 12 has the columned rotor core (iron core) 15 being made up of iron material etc., is arranged at this at predetermined intervals Multiple permanent magnets 16 of the outer peripheral face of rotor core 15, the multiple magnet insertion grooves 17 for accommodating permanent magnet 16.This embodiment party R-T-B systems sintered magnet involved by formula is used for permanent magnet 16.To be inserted along the circumferencial direction of rotor 12 in each magnet Enter the mode that N poles and S poles are alternately arranged in groove 17 and multiple permanent magnets 16 are set.Thus, circumferentially it is adjacent forever Diametric(al) of the long magnet 16 along rotor 12 produces the magnetic line of force of mutual opposite direction.

Stator 13 has along the outer peripheral face of rotor 12 in the peripheral direction of the inside of its barrel (peripheral wall) to provide Spaced multiple stator cores 18 and choke valve 19.The plurality of stator core 18 is with towards the center of stator 13 and with turning Sub 12 relative modes are set.In addition, it is wound with coil 20 in each choke valve 19.Permanent magnet 16 and stator core 18 with Mutually relative mode is set.

Rotor 12 together with rotary shaft 14 in a manner of it can rotate with being arranged in the space in stator 13.Stator 13 is logical Cross electromagnetic action and assign moment of torsion to rotor 12, so as to which rotor 12 rotates in a circumferential direction.

SPM motor 10 use the R-T-B systems sintered magnet involved by present embodiment as permanent magnet 16.Due to forever Long magnet 16 is with corrosion resistance and with high magnetic characteristic, so SPM motor 10 can improve the torque characteristics of motor Deng the performance of motor, and there can be high-output power for a long time, and it is excellent in reliability.

In addition, the present invention is not limited to above-mentioned embodiment, various changes can be carried out within the scope of the invention.

Embodiment

Hereinafter, embodiment is enumerated further to specifically describe the present invention, but the present invention is not limited to following implementation Example.

First, connected in a manner of obtaining having the composition of the magnet shown in Tables 1 and 2 I and II sintered magnet by strip Casting prepares raw alloy.As raw alloy, making has prepared to primarily form the 1st alloy A and B, the master of the principal phase of magnet The 2-in-1 golden a and b for forming crystal boundary amounts to 4 kinds.In addition, bal. is represented respectively in Tables 1 and 2 (table 3 described later is similarly) The overall composition of alloy as 100 mass % in the case of surplus, total quality % of (T.RE) expression terres rares.

[table 1]

[table 2]

Next, making hydrogen be adsorbed in after alloy at room temperature respectively, it is small to implement progress 1 under an ar atmosphere at 600 DEG C When dehydrogenation hydrogen pulverization process (coarse crushing).

In addition, in the present embodiment, carried out under Ar atmosphere of the oxygen concentration less than 50ppm from the hydrogen pulverization process to sintering Each process (Crushing of Ultrafine and shaping) (identical in following embodiment and comparative example).

Then, for each alloy, before carrying out Crushing of Ultrafine after hydrogen crushing, 0.1 mass % is added in coarse powder comminuted powder Zinc stearate as grinding aid, mixed using nauta mixer (Nauta mixer).Here, only formed in magnet 0.1 mass % carbon black is also added in II 2-in-1 golden b in addition to zinc stearate.Afterwards, micro mist is carried out using airflow milling It is broken, micro mist comminuted powder of the average grain diameter for 4.0 μm of degree is made.

Afterwards, using nauta mixer by the micro mist comminuted powder of the 1st alloy and 2-in-1 golden micro mist comminuted powder with 95:5 Part by weight mixes, and modulates the mixed-powder of the material powder as R-T-B systems sintered magnet.

Obtained mixed-powder is filled in configuration in the mould in electromagnet, carried out while applying 1200kA/m magnetic On one side application 120MPa pressure magnetic field in be molded, obtain formed body.

Afterwards, obtained formed body is kept at 1060 DEG C in a vacuum implement to sinter within 4 hours, then, carried out anxious It is cold, obtain having the sintered body (R-T-B systems sintered magnet) of the magnet composition I shown in table 1.Then, obtained magnet is processed Into 13.2mm × 8.2mm × 4.2mm cuboid.Make R₂T₁₄The differently- oriented directivity of the c-axis of B crystal grain turns into 4.2mm thickness direction.

(comparative example 1)

It is small to implement at 850 DEG C at 1 hour, then 540 DEG C 2 to the composition of obtained magnet with the aforedescribed process I sintered body When 2 stages (all under an ar atmosphere) Ageing Treatment.Thereafter, each face of sintered body is ground each 0.1mm with processing machine, obtained 13mm × 8mm × 4mm R-T-B systems sintered magnet.As comparative example 1.

(embodiment 1)

It is small to implement at 850 DEG C at 1 hour, then 540 DEG C 2 to the composition of obtained magnet with the aforedescribed process II sintered body When 2 stages (all under an ar atmosphere) Ageing Treatment.Thereafter, each face of sintered body is ground each 0.1mm with processing machine, obtained 13mm × 8mm × 4mm R-T-B systems sintered magnet.As embodiment 1.

(embodiment 2~6)

Embodiment 2~6 be an attempt to magnet composition I R-T-B systems sintered magnet grain boundary decision method by Cu, Ga, Si, Ge, Bi, C are imported into crystal boundary, form the example of R-Cu-M-C concentrating part.Table 3 is the composition of weighing in the diffusion source made.With table Composition shown in 3 weighs metal simple-substance, repeats 3 melting castings with electric arc melting furnace to make alloy.Pass through high frequency The alloy molten that sensing heating will obtain, by the way that chilling strip is made to molten metal rolling chilling.The chilling that will be obtained Strip carries out coarse crushing in the glove box of Ar atmosphere, is put into an ar atmosphere in closed container together with steel medium. Thereafter, crushed in closed container, obtain the powder that average grain diameter is 10~20 μm.In obtained diffusion material powder Resin glue is added, the coating of diffusion material is made using alcohol as solvent.For blending ratio, by diffusion material powder Weight will be 2 as the butyral micropowder of resin glue as in the case of 100, alcohol 100.Setting in an ar atmosphere Add said mixture in the cylindrical shape container with a lid of fat to close the lid, be placed on ball mill pedestal makes under 120rpm Rotation 24 hours, carry out coating.Magnet composition I sintered body processed goods is impregnated in obtained coating, taking-up is done It is dry.The process is repeated, is coated with 2.5% amount of sintered body processed goods weight.Thereafter, implement in an ar atmosphere 6 small at 900 DEG C When, the then heat treatment of 2 hours at 540 DEG C.After heat treatment, with sand paper by the residue of the diffusion material on sintered body surface gently Cut, then, each face is ground each 0.1mm with processing machine, obtains R-T-B systems sintered magnet.Use each composition shown in table 3 Diffusion material makes sample by above-mentioned method, obtains embodiment 2~6.

[table 3]

(embodiment 7~8)

Embodiment 7~8 is that Ga is imported into crystal boundary by magnet composition I R-T-B systems sintered magnet with grain boundary decision method, Trial forms the example of R-Cu-Ga-C concentrating part.Magnet composition is impregnated in the above-mentioned coating of the diffusion material containing Ga of table 3 I sintered body processed goods, taking-up are dried.By repeating the process, so that coating weight is：It is sintering in embodiment 7 Body weight 1.6%, in embodiment 8 for sintering body weight 0.6%.Thereafter, in an ar atmosphere implement 900 DEG C at 6 hours, Then the heat treatment of 2 hours at 540 DEG C.After heat treatment, the residue of the diffusion material on sintered body surface is gently cut with sand paper Fall, then, each face is ground each 0.1mm with processing machine, obtains 13mm × 8mm × 4mm embodiment 7 and 8.

[composition analysis]

For the R-T-B systems sintered magnet obtained in embodiment 1~8 and comparative example 1, pass through fluorescent x-ary analysis And inductively coupled plasma mass spectrometry (ICP-MS methods) carries out composition analysis.Show the result in table 4.

[table 4]

[tissue]

(observation of Elemental redistribution)

Removed on the surface of the section for the R-T-B systems sintered magnet that embodiment 1~8 and comparative example 1 are pruned with ion etching Go after the influence of the oxidation of most surface etc., with EPMA (electron probe microanalyzers：Electron Probe Micro Analyzer) to the cross-section Elemental redistribution of R-T-B systems sintered magnet, and analyzed.For the region of 50 μm of square, use The tissue of the R-T-B systems sintered magnet of EPMA observation embodiments 4, and row element is entered by EPMA and surveys and draws (element Mapping) (256 points × 256 points).By Nd, Cu, M, C of the R-T-B systems sintered magnet section of embodiment 1 each element The observation result obtained by EPMA is shown in Fig. 4~8.In addition, the R by the R-T-B systems sintered magnet section of embodiment 1 (Nd, Pr), Cu, M (Ga), C each element concentration distribution higher than principal phase crystal grain in region (R-Cu-M-C concentrating part) show In Fig. 9.

(calculating of the area ratio in crystal boundary shared by R-Cu-M-C concentrating part)

With the surveying and mapping data of embodiment 1~8 and the R-T-B systems sintered magnet of comparative example 1 according to order as described below Calculate the area ratio (A/B) in crystal boundary shared by R-Cu-M-C concentrating part.(1) with defined level to backscattered electron image Image carries out binaryzation, it is specified that main phase grain part and grain boundary portion, calculates the area (B) of grain boundary portion.In addition, binaryzation It is to be carried out on the basis of the signal intensity of backscattered electron image.The content more at most back scattering of the big element of known atom sequence number The signal intensity of charge pattern becomes stronger.The rare earth member big compared to the more atom sequence numbers in principal phase part in grain boundary portion be present Element, it is the method generally carried out with the next specific main phase grain part of prescribed level progress binaryzation and grain boundary portion.In addition, even if Binaryzation is carried out during measure and generates two particle grain boundary portions not by specific part, this is not by specific two particles crystal boundary In the error range of part and grain boundary portion entirety, when calculating area (B) of grain boundary portion, logarithm value scope does not produce shadow Ring.

(2) from the surveying and mapping data of R, Cu, M, the C obtained by EPMA characteristic X-ray intensity, calculate special by above-mentioned (1) The average value and standard deviation of the characteristic X-ray intensity of each element of R, Cu, M, C in fixed main phase grain part.

(3) according to the surveying and mapping data of the characteristic X-ray intensity by obtained R, Cu, M, the C of EPMA, to the specific spy of each element Property X-ray intensity value be more than characteristic X-ray intensity in the main phase grain part tried to achieve by above-mentioned (2) (average value+3 × Standard deviation) value part, the part is defined as the concentration of the element higher than the part (concentration being distributed in main phase grain Portion).

(4) concentrating part of R element (is Nd in embodiment 2 for each R element in the concentrating part of above-mentioned (3) specific each element And Pr) any part being distributed in high concentration.The concentrating part of Cu elements is the part of Cu high concentrations distribution.For the dense of M Contracting portion, M have it is a variety of in the case of, be each M any part being distributed in high concentration.The concentrating part of C element is C high concentrations The part of ground distribution.

(5) will be brilliant with being higher than principal phase respectively with concentration by above-mentioned (4) specific R, Cu, M, C by above-mentioned (1) specific crystal boundary All overlapping part specifically for the R-Cu-M-C concentrating part in crystal boundary, and calculates the area of the part for the part of intragranular distribution (A)。

(6) by being calculated by the area (A) of the R-Cu-M-C concentrating part calculated by above-mentioned (5) divided by by above-mentioned (1) Crystal boundary area (B), so as to calculate the area ratio (A/B) in crystal boundary shared by R-Cu-M-C concentrating part.

By R-Cu-M-C in the crystal boundary of the embodiment 1~8 thus tried to achieve and each R-T-B systems sintered magnet of comparative example 1 Area ratio (A/B) shared by concentrating part is shown in Table 5.

[table 5]

(Cu and M atoms relative to ratio (Cu+M)/R of R atoms calculating)

Then, quantitative analysis is carried out to the composition of R-Cu-M-C concentrating part.It is dense to surveying and drawing specific R-Cu-M-C with EPMA Contracting portion, the quantitative analysis of each element is carried out using EPMA, it is relative to calculate Cu and M atoms according to the concentration for each element tried to achieve In ratio (Cu+M)/R of whole R atomicities.At 1 sample measure 10, the value of (Cu+M)/R everywhere is tried to achieve.By each sample (Cu+M)/R maximum, minimum value are shown in Table 5 in product.In addition, the composition example as R-Cu-M-C concentrating part, by embodiment 2 analysis result of R-T-B systems sintered magnet and (Cu+M)/R value is shown in Table 6.

[table 6]

[magnetic characteristic]

By the overlapping 3 progress 3T of sample (13mm × 8mm × 4.0mm) difference of each embodiment, comparative example impulse magnetization Afterwards, demagnetizing curve is determined using magnetic characteristic tape deck (B-H tracer).The residual flux that will be tried to achieve according to demagnetizing curve Density Br, coercivity H J are shown in Table 5.

[corrosion resistance]

The R-T-B systems sintered magnet of comparative example 1 and embodiment 1~8 is put into PCT (pressure cooker test) groove, placed 200 hours in 120 DEG C, 2 atmospheric pressure, the saturated steam atmosphere that relative humidity is 100%, the weight as caused by corrosion is evaluated Measure decrement.It the results are shown in Table 5.

Illustrated for the comparative result of the fine structure of each sample, corrosion resistance, magnetic characteristic.As shown in table 5, than Compared with the presence that not can confirm that R-Cu-M-C concentrating part in the sample of example 1.On the other hand, in each sample of comparative example 1~8 really Recognizing has the presence of R-Cu-M-C concentrating part.Further, increased by R-Cu-M-C concentrating part area shared in crystal boundary, as Weight after the PCT200 hours of the index of corrosion resistance, which is reduced, to diminish, so as to improve corrosion resistance.

R-Cu-M-C concentrating part area shared in crystal boundary more increases, and more has the tendency of corrosion resistance improvement, if R- Cu-M-C concentrating part area shared in crystal boundary is more than 1%, then effect is especially high.In addition further, obtain it is especially good In the embodiment 2,3,4 of good result, more than 2% area has been obtained.

Further, it is known that if be conceived to by (the Cu+M)/R for forming to obtain of R-Cu-M-C concentrating part value, aobvious Show in the embodiment 2,3,4 of especially good corrosion resistance, (Cu+M)/R value is 0.2~0.6 scope.Implement in others In example, minimum value is less than 0.2 or maximum more than 0.6 or is both.I.e., it is possible to think, in order to improve corrosion resistance, have The compositing range of particularly preferred R-Cu-M-C concentrating part, it is believed that can effectively suppress by crystal boundary within the above range Hydrogen adsorb and caused by corrosive cycle progress.

If being conceived to magnetic characteristic, the reduction relative to comparative example residual magnetic flux density Br in embodiment is small, coercive Power HcJ is slightly improved.Keep having excellent magnetic characteristics in embodiment i.e., it is possible to say, also significantly improve corrosion resistance.

Table 6 is the example of the composition of R-Cu-M-C concentrating part, in the embodiment 2 of especially good corrosion resistance is shown It is confirmed that.

(embodiment 9~12)

The R-T-B systems sintered magnet of magnet composition II~VI shown in table 7~10 is made, until the process of molding procedure is all Carried out with method same as Example 1, in any 2-in-1 golden Crushing of Ultrafine except 0.1 mass % zinc stearate with The outer carbon black that all with the addition of 0.1 mass %.Obtained the 1st alloy, 2-in-1 golden mixing, shaping are entered in the same manner as comparative example 1 OK.After the temperature that sintering circuit is carried out 4 hours at the temperature shown in table 11 is kept, chilling is carried out.Thereafter, implement 850 The Ageing Treatment in 2 stages of 2 hours (all under an ar atmosphere) 1 hour at DEG C, then at 540 DEG C.Thereafter, with processing machine to burning Each face of knot body is ground each 0.1mm, obtains 13mm × 8mm × 4mm R-T-B systems sintered magnet.4mm thickness direction is R₂T₁₄The differently- oriented directivity of the c-axis of B crystal grain.

[table 7]

[table 8]

[table 9]

[table 10]

[table 11]

(embodiment 13~17)

Embodiment 13~17 forms making to distinguish identical with embodiment 9~12, but dense for forming R-Cu-M-C The adding method of the carbon in contracting portion is different.In embodiment 13~17,0.1 mass % is added in 2-in-1 golden coarse powder comminuted powder Carbon black, after being mixed with nauta mixer, in an ar atmosphere carry out 600 DEG C of 1h heat treatment.Thereafter Crushing of Ultrafine work Sequence, molding procedure are identical with comparative example 1.In sintering circuit, in order to promote the formation of R-Cu-M-C concentrating part, in way of heating up 700 DEG C at keeping temperature 24 hours.After heating, keeping temperature 4 hours at the temperature shown in table 11, then, carry out anxious It is cold.Afterwards, implement at 850 DEG C 1 hour, then at 540 DEG C 2 stages of 2 hours (all under an ar atmosphere) Ageing Treatment. Thereafter, each 0.1mm is ground to each face of sintered body with processing machine, obtains 13mm × 8mm × 4mm R-T-B systems sintered magnet. 4mm thickness direction is R₂T₁₄The differently- oriented directivity of the c-axis of B crystal grain.

As shown in table 11, in embodiment 1 and embodiment 9~17, it is thus identified that the presence of R-Cu-M-C concentrating part and The improvement of corrosion resistance.The ratio of R-Cu-M-C concentrating part is high particularly in embodiment 13~17, and (M+Cu)/R is 0.2~ 0.6 scope, show good corrosion resistance.

According to identified above in the R-T-B systems sintered magnet of embodiment, there is R-Cu-M-C concentrating part in crystal boundary, So as to maintain good magnetic characteristic, and significantly improve corrosion resistance.

Claims

A kind of 1. R-T-B systems sintered magnet, it is characterised in that

R-T-B systems sintered magnet has R₂T₁₄B crystal grain,

By the adjacent R of more than 2₂T₁₄There is R-Cu-M-C concentrating part in the crystal boundary that B crystal grain is formed, compared to described R₂T₁₄In B crystal grain, R, Cu, M, C of the R-Cu-M-C concentrating part concentration are all higher, wherein, the R is selected from rare earth element In it is at least one kind of, M to be at least one kind of in Ga, Si, Sn, Ge, Bi, T represent a kind comprising Fe or comprising Fe and Co with On transition metal,

It is relative to the ratio between whole R atomicities, (Cu+M)/R as the total of Cu and M atoms in the R-Cu-M-C concentrating part More than 0.2 and less than 0.6.
2. R-T-B systems as claimed in claim 1 sintered magnet, it is characterised in that

In the section of R-T-B systems sintered magnet, R-Cu-M-C concentrating part area shared in the crystal boundary is More than 1%.
3. R-T-B systems as claimed in claim 1 or 2 sintered magnet, it is characterised in that

In R-T-B systems sintered magnet, containing Cu, M, Al,

The content of each element of R-T-B systems sintered magnet is：

R：29.5~33 mass %；

B：0.75~0.95 mass %；

M：0.05~1.0 mass %；

Cu：0.05~0.55 mass %；

Co：0.3~3.0 mass %；

Al：0.03~0.6 mass %；

Fe：Substantial surplus.
4. R-T-B systems as claimed in claim 1 or 2 sintered magnet, it is characterised in that

In R-T-B systems sintered magnet, containing Cu, M, Al,

The content of each element of R-T-B systems sintered magnet is：

R：29.5~32.0 mass %；

B：0.75~0.95 mass %；

M：0.05~1.0 mass %；

Cu：0.05~0.55 mass %；

Co：1.0~2.0 mass %；

Al：0.05~0.25 mass %；

Fe：Substantial surplus.
5. R-T-B systems as claimed in claim 1 or 2 sintered magnet, it is characterised in that

Contain Zr in R-T-B systems sintered magnet, Zr content is more than 0.01 mass % and below 1.5 mass %.
6. R-T-B systems as claimed in claim 1 or 2 sintered magnet, it is characterised in that

Contain O in R-T-B systems sintered magnet, O content is below 2000ppm.
7. R-T-B systems as claimed in claim 1 or 2 sintered magnet, it is characterised in that

Contain C in R-T-B systems sintered magnet, C content is 500-1500ppm.
8. a kind of motor, wherein,

R-T-B systems according to any one of claims 1 to 7 sintered magnet is used.